11/13/2013 - By Matthew Shultz

Look up in the air. Is it a bird or is it a plane… no it is just a cloud of Rugose Spiraling Whitefly. Living in Florida can be exciting, with monitor lizards feeding on small dogs on canal banks and reticulating pythons swallowing 8 ft. alligators. This is not science fiction folks, it is the real deal. Florida being a hub of shipping lanes from all over the world, our visitors are not only pasty white people wearing socks and sandals, but also hitch hiking insect pests from worlds beyond.

Not a week goes by that I do not get a call regarding the Rugose Spiraling Whitefly, formally known as the Gumbo Limbo Spiraling Whitefly. The name was changed when it was apparent the Gumbo Limbo tree was only one of the hosts this pest invades. Aleurodicus rugioperulatus is the scientific name. This pest from Central America has slammed into South Florida and parts of Central Florida in a big way, primarily affecting landscapes, but also tree field nurseries. Many palms, especially coconuts, white birds of paradise, Gumbo Limbo trees, Callophyllum and other tree varieties have their canopies covered in the white/waxy flocculent and black sooty mold, the calling card of this pest.

Whitefly Egg Mass - Photo by Matt Shultz

Like any whitefly, the adult lays its eggs on the undersides of the host plant leaves. The Rugose Spiraling Whitefly lays its eggs in a distinctive spiral like pattern. Once the eggs hatch into nymphs, this is where the parasitic nature of this pest happens. With piercing sucking mouth parts, the nymphs suck plant juices or sap from the leaves. This weakens the host plant. The waste or exudate left by the nymph or larvae is a sticky substance often called honey dew. The saprophytic fungi sooty mold feeds upon this honey dew and walah, you have a tree completely black, your carport and driveway black as well. Most of these new pests come in with a vengeance initially and eventually wane as natural predators catch on. But this scenario has been going on several years without any reprieve from them.

The best control is a blow torch fueled by petroleum. But if you insist on saving your tree, the neonicatinoid family of insecticides is working best. For landscapers Merit or Criterion are quite good. As is Dinotefuron, also known as Safari. For trees too large to spray, applying the granular neonic’s is good, taking at least a month for control in larger trees. Some pest control companies are getting results with injections of Tristar, a liquid neonicatinoid. Please follow the label on all of this. Entomologists warn that using broad spectrum insecticides risk killing any natural predator potential, especially the contact types. To help avoid resistance in the whiteflies, products like Acephate and/or Talstar are good alternatives.

Insecticidal soaps and refined spray oils also help in control of this pest. It is said this pest will not “kill” a tree or palm. But it sure makes them unsightly. In Pine Island a week ago, I saw a field palm nursery using a pressure washer on trees they were shipping. The leaves wre pitch black with sooty mold. They were trying to minimize the infestation. To me it was like trying to use a garden hose to create a high tide in the Atlantic Ocean. Eventually we should see a natural predator rise from the brush. Until then…happy spraying.